Methods: In this study, the dystrophin gene from M. rosenbergii (MrDys) was first characterised followed by the characterization of dystrophin gene from a closely related shrimp species, Penaeus monodon (PmDys). Dystrophin sequences from different phyla were then used for evolutionary comparison through BLAST analysis, conserved domain analysis and phylogenetic analysis. The changes in mRNA expression levels of dystrophin and the alteration of intracellular calcium concentrations in WSSV infected muscle cells were then studied.
Results: A 1246 base pair long dystrophin sequence was identified in the giant freshwater prawn, Macrobrachium rosenbergii (MrDys) followed by 1082 base pair long dystrophin sequence in P. monodon (PmDys). Four conserved domains were identified from the thirteen dystrophin sequences compared which were classified into 5 different phyla. From the phylogenetic analysis, aside from PmDys, the characterised MrDys was shown to be most similar to the invertebrate phylum of Nematoda. In addition, an initial down-regulation of dystrophin gene expression followed by eventual up-regulation, together with an increase in intracellular calcium concentration [Ca2+]
were shown upon WSSV experimental infection.
Discussion: Both the functionality of the dystrophin protein and the intracellular calcium concentration were affected by WSSV infection which resulted in progressive muscle degeneration. An increased understanding of the role of dystrophin-calcium in MrDys and the interactions between these two components is necessary to prevent or reduce occurrences of muscle degeneration caused by WSSV infection, thereby reducing economic losses in the prawn farming industry from such disease.
Objectives: We aimed to systematically produce empirical evidence on the WPV against health care workers in Africa through the review of relevant literature.
Method: We sourced for evidence through the following databases: PubMed, Science direct and Scopus from 30th November to 31st December 2019 as well as the reference list of the studies included. A total of 22 peer reviewed articles were included in the review (8065 respondents). Quality appraisal of the included studies was assessed using critical appraisal tools for cross-sectional studies.
Result: Across the studies, diverse but high prevalence of WPV ranging from 9% to 100% was reported with the highest in South Africa (54%-100%) and Egypt (59.7%-86.1%). The common types were verbal, physical, sexual harassment and psychological violence. The correlates of WPV reported were gender, age, shift duty, emergency unit, psychiatric unit, nursing, marital status and others. Various impacts were reported including psychological impacts and desire to quit nursing. Patients and their relatives, the coworkers and supervisors were the mostly reported perpetrators of violence. Doctors were mostly implicated in the sexual violence against nurses. Policy on violence and management strategies were non-existent across the studies.
Conclusion: High prevalence of WPV against healthcare workers exists in Africa but there is still paucity of research on the subject matter. However, urgent measures like policy formulation and others must be taken to address the WPV as to avert the impact on the healthcare system.